Latch fastening for doors, windows, and the like



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LATCH FASTENING FOR DOORS, WINDOWS AND THE LIKE Filed March 25, 1934- atented pr. 2, l3

LATCH FASTENING FOR HOURS, WJIINDUWS, AND THE LIKE Gustaaf Adolf Agterberg,

Amsterdam, Netherlands, assignor of one-half to Simon .l'ohannes van den Berg, Amsterdam, Netherlands Application March 23, 1934, Serial No. 717,068 in Germany April 1, 1933 2 @lairns.

This invention comprises improvements in latch iastenings for doors, windows and the like of the push-pull type, i. e. the type in which the latch is freed from engagement with the striker plate on the doorpost to perrrit the door to open by a push or pull on the door handle in a direction normal to the plane of the door, a push on the handle being required to open the door from one side thereof and a pull on the handle being required to open the door from the other side there- In fastenings of this type as hitherto proposed rollers have been employed to hold the door in the closed position, but it is found that if this construction is adopted the latch will open by pressure on the door itself instead of opening only on application of a push or pull movement to the handle.

It is the object of the present invention to provide a latch fastening of the push-pull type for doors, windows and the like which can only be opened by operation of the handle itself and which, while holding the door firmly closed, will nevertheless yield to the lightest touch on the handle and with the minimum of noise. With this object in view the invention provides the novel combination of parts hereinafter more fully described and pointed out in the accompanying claims.

A particular construction of a door fastening in accordance with the invention will now be described in detail, by way of example, with reference to the accompanying drawing in which:

Figure 1 is a plan view of the latch, partly in section.

Figures 2 and 3 are detail views showing respectively the action of the loose tooth on opening and closing the door, and

Figure 4 is a fragmentary end elevation of the loose tooth.

Like reference numerals indicate like parts throughout the drawing.

The mechanism is contained in an L-shaped box it fitted with its longer limb extending along the outer side of the door l l (i. e. the side opposite the direction in which the door opens) and with its shorter limb on the face of the door which abuts against the door post H2. The box may be entirely or partly mortised into the door but as a very small part only of the door needs to be cut away the strength of the door is in no way impaired. The door handle comprises a stem 93 fitted at its opposite ends with knobs M, 5 projecting one on each side of the door, and supported respectively in sleeves I6, ll of metal or other material screwed or otherwise secured one on either side of the door so as to project therefrom, the arrangement being such that in the normal position of the handle the knob it on the inner side of the door lies substantially against the outer end of its associated sleeve ll whilst the knob i l on the outer side of the.,door projects from its associated sleeve [16. A compression spring 53 which abuts at one end against a seating #9 on the sleeve l and at the other end against a flange Zil projecting from the stem it of the handle maintains the handle in this position.

The stem of the handle is cut away adjacent the knob M on the outer side of the door to form a surface 2i which slants from said knob towards the axis of the handle. Against this surface abuts a roiler 22 carried on a bar 23 which is arranged to slide along a guide 2 1 (constituted by the inner surface of the longer limb of the L-shaped box it) extending at right angles to the axis of the handle. Rollers 25, 25 mounted in the L-shaped box and haxing axes parallel to the roller on the bar are in contact respectively with the side of the handle stem 43 opposite to the bar 23 and the side of the bar 23 opposite to the wall of its guide 23 i and serve to steady the movements of the handle and bar.

The door latch member 2i which is of sector shape in section, is pivoted at a point 28 corresponding to the centre of the sector to the L- shaped box, the axis of pivoting being located near the corner of the L. One edge of the latch member 2'! projects through an aperture 29 in the shorter side of the L and is adapted to engage a striker plate ti! on the door post l2. This striker plate is of the usual construction but instead of having a hole to receive the latch member it is provided with a metal rim ti on the side to which the door moves on opening, which rim extends at right angles to the plane of the striker plate and which serves to engage the latch member 22. The latch member has a coiled spring 32 around its pivot 23, and this spring tends to hold the latch member in engagement with the striker plate. The latch member is formed on the side of its pivot remote from its engaging end, with a projection 33 which is held against the bar 23 by the spring 32.

It will be appreciated therefore that if the handle is moved into the door by a push on its outer knob it or a pull on its inner knob it the action of the slanting face 2! on the handle stem on the bar will be to urge the bar 23 along its guide 2t away from the axis of the handle and 2 therefore to turn the latch member 21 about its pivot 28 against the action of the spring 32 into a position in which it will be freed from the striker plate 30 so that continued push or pull on the handle will result in the door being opened.

In order to effect disengagement of the latch member from the striker plate the latch member is arranged to engage with the rim of the striker plate by a loose tooth 34 pivoted to the outside corner of the latch member by means of a pin 35.

As will be seen from Figure 4 the loose tooth 34 is in the form of a triangular prism having its edges disposed vertically and formed approximately midway in one of its faces with a projection 36 by means of which the tooth is pivoted to the latch member, a slot in the latch member receiving the projection 36 on the tooth. The slot is so formed that the tooth has a limited free movement of about 50-60 in an outward direction from the position shown in Figure 3 in which the shoulders 31 on the side of the tooth nearest the striker plate contact with the inside surface of the latch member, to the position shown in Figure 2 in which the shoulders 3i contact with the outside surface of the latch member.

If the tooth 34 were to be fixed to the latch member 21 instead of being loosely connected thereto, or if the latch member had a simple sharp edge, experience has shown that the latch member cannot be turned in however light or hard a push is applied to the door knob, since the stronger the push the greater the indirect pressure on the door, and the more strongly the edge of the latch member is pressed against the rim of the striker plate.

When the latch member is provided with a loose tooth, in the manner described above, on shutting the door the loose tooth is pressed or shifted in an inward direction by the doorstile and striker plate. This action is shown in Figure 3. The rim 3| first turns the loose tooth into the limiting position in which the shoulders 31 abut against the latch member, and then the latch member as a whole is moved about its pivot 28 against the action of the spring 32 by an amount sufficient for the latch member to clear the rim. The latch member is then snapped back by the spring so that the tooth engages the striker plate to hold the door closed. As soon, however, as an inward push is applied to the knob M on the outside of the door (or a pull to the knob 15 on the inside of the door) the pressure of the spring 32 on the latch member is eliminated and the loose tooth 34 released from the outward pressure upon it. Consequently, since at the same time an indirect inward push has been exerted on the door, the tooth will tend to tilt forwards (i. e. in an outward direction) as shown in Figure 2, so that there is no further obstruction to the latch member, the latch member and tooth being free to turn completely in, missing the rim of the striker plate, with the result that the door is opened.

The advantage of the provision of the loose tooth is that immediately the door knob is touched and the latch member commences to turn about its pivot the loose tooth will fall forward so as to become freed from the catch rim of the striker plate thus ensuring a prompt and noiseless loosening of the latch, with minimum expenditure of effort on the handle.

It will be understood that while the invention has primarily been described with reference to its application to doors, it may nevertheless also be applied to windows and the like, in which case the striker plate would be mounted in the window jamb. The invention is particularly suitable for doors for motor cars.

What I claim as my invention and desire to secure by Letters Patent is:-

l. A latch fastening of the push-pull type for doors, windows and the like, comprising in combination a latch member pivoted on the door adapted to cooperate with a striker plate in the door post, a tooth mounted on the outer end of the latch member for limited pivotal movement relatively to said latch member constituting therewith a toggle, a spring urging the latch member towards the projected position and adapted to hold the tooth aforesaid in engagement with the striker plate to maintain the door closed, and means on the door for moving the latch member about its pivot against the action of the spring to break the toggle between the tooth and the latch member, the tooth having a shoulder arranged to engage the latch member to move the latter about its pivot against the action of the spring as the tooth engages the rim of the striker plate on movement of the door to the closed position.

2. A latch fastening comprising a pivoted latch member, means biasing the latch member to operative position, a striker plate engaging member pivoted to the end of the latch member, said striker plate engaging member having oppositely disposed cam faces and formed with shoulders adapted to engage the latch member and limit its pivotal movement in each direction, constituting therewith a toggle, a lineally movable knob assembly, and means connecting the knob assembly and the latch member, whereby an initial lineal movement of the knob assembly will rock the latch member to break the toggle and movement of the door in opening will further rock the latch member to clear the striker plate.

GUSTAAF ADOLF AGTERBERG. 

